/Engine/Source/Runtime/GeometryCore/Public/Sampling/MeshSurfacePointSampling.h
The strategy used is to compute a much higher density sampling than needed (based on .SubSampleDensity), then iteratively select from that point set and decimate it within the radius of selected samples. The implementation also introduces various biases to increase performance. Generally increasing SubSampleDensity will result in more tightly-packed results, but at increasingly expensive computation time.
void ComputePoissonSampling ( const [FDynamicMesh3](API\Runtime\GeometryCore\DynamicMesh\FDynamicMesh3) & Mesh, [FProgressCancel](API\Runtime\GeometryCore\Util\FProgressCancel) * Progress )